Washout : I've noted your idea, and we'll see what we can do about it when we have a really working version (soon
However, if you compare byte to byte the original files and the new ones, they're not the same (though they have the same size, at least for Vietnam) : that's because, I think, I do not calculate duplicate regions in the same way it was done originally (i.e. tiles in L2 are not in the same order).
There's just one trick left to investigate, about ocean tiles being at offset 0. I'm not sure this an issue at all, but I must check that with Dr. Fred Balding.
Regardless of this trick, all I have to do now is implement the BMP rules (it should not take me long) : so, theorically, you should have a working version today
Regards.